Reversible heating and cooling system



Oct. 23, 1951 A. KRUEGER REVERSIBLE HEATING AND COOLING SYSTEM 2 SHEETS- -SHEET 1 INVENTOR.

Filed May 5, 1948 hill u no "no (l/klask Oct. 23, 1951 A, KRUEGER 2,572,356

REVERSIBLE HEATING AND COOLING SYSTEM Filed May 5, 1948 2 SHEETS-SHEET 2 Patented Oct.v 23 1951 UNITED REVERSIBLE HEATING AND COOLING SYSTEM Frank A. Krueger, Shawano, Wis.

Application May 5, 1948, Serial No. 25,283

Claims. 1

This invention relates to a reversible heat pump. More particularly, it relates to a heat pump, primaril for installation in private homes, which employs a compressor and two sets of coils which may be used interchangeably as evaporators or condensers. Applicant's system employs water drawn from the earth for providing heat or removing heat.

The first object of this invention is to provide an open duct refrigerating system, by which applicant means one which has neither check valves, nor expansion valves, nor float valves between the low side of the compressor at one end of the refrigerating system and the high side of the compressor at the other end of the refrigerating system. This objective is important in a refrigerating system. IIn the ordinary system, such as in a household refrigerator, any number of check valves, float valves, or expansion valves may be inserted in the system because the flow of refrigerant is always in one direction. In the reversible heat pump, the flow is in either direction. If the line contains several check valves and float valves, which will cause the system to function when the refrigerant is flowing in one direction, these valves must be rendered inoperative and other valves brought into operation if the system is to function in the reverse direction.

Another feature of applicant's invention is what he refers to as his balanced system by which he means the provision of two sets of coils and accumulators which have approximately the same volumetric capacity in-a refrigerant line which has no valves in it, with the result that the system can go from a heating system to a refrigerating system by simply reversing the direction of flow of refrigerant. The operation of the device will be explained in the description.

The second object of this invention is to provide a muilier which will kill the pounding noise of the pump when forwarding refrigerant to the coils. the high side of a piston type pump leads to the condenser coils, which in turn feed an accumulator. Each time the pump forces a quantity of gas into the tubing of the condenser there is a. throb or noise. The noise is not great in the case of small compressors. In heat pumps, however, where one is using four cylinder pumps driven by four or five horsepower motors, this throb is very noisy. .One of the features of applicants invention is positioning an accumulator between the coils and the high side of the pump. This accumulator acts something like an automobile muiiier. The compressed gas is forced into the In an ordinary refrigerator the output on accumulator and is then carried out a plurality of passageways into the condenser.

The third object of this invention is to provide a system which circulates water from the ground to the point of use and back into the ground. Many of the heat pumps that rely upon water for withdrawing heat from the earth position a water line and return water line, that is a closedcircuit, down into the earth for several hundred feet. The ability of these systems to function depends on the rate of heat transfer from the earth through the pipe into th water. Applicants system does not employ such a closed pipe circuit. On the contrary, applicant's system draws water from the ground, twenty-five feet or so below the surface, uses it, and then puts it back into the ground twenty-five feet below the surface at some distance from where it was taken out.

The foregoing objects have all been attained, for the invention here disclosed was built by applicant and placed in operation at applicant's home at Shawano. Wisconsin, in the full of 1947, The device has heated a story and half house, seven rooms, with a, basement approximately thirty-four feet square, to an average temperature of '72 degrees when outside temperatures were as low as 2'7 degrees below zero. The cost of electricity has averaged approximately 41 cents a day,

In the description that follows, applicant's system is described in two ways, first schemati cally, in connection with Figs. 1 and 2; andsecondly, factually, in connection with Figs. 3, 4 and 5, which are plan, side and end elevations of the system installed in applicant's home at Shawano.

Continuing to refer to the drawings, in Fig. 1, the numeral l0 identifies a compressor and the numerals 12 and I4 identify heat exchange units. Each heat exchange unit consists of a battery of coils l6 and I8 connected to accumulators 20 and 22. The coils l6 and I8 are connected to each other by a capillary tube 24. The accumulators are connected to a reversing assembly 26 which in turnis connected to the compressor It.

It will be noticed that there are no valves in the system, other than the reversing valves, or the valves in the compressor. There are no check, valves or expansion valves.' For this system to work, the important thing is this: The cubic content of the heat exchanger l2 which includes the coil I6 and the accumulator 20 should be approximately equal to the cubic content of the heat exchanger [4 which includes the coils I8 and the accumulator 22. It is not necesamazing any that the cubic content of the accumulator 20 be equal to that of the accumulator 22 or-that the content of the coil It be equal to the content of the coils II. If the heat exchanger I2 is positioned in a flow of air, the rate of heat transfer is slower-than the rate for the coils I! if they are positioned in water, and applicant, consequently, may utilize coils having less cubic content in the heat exchanger l4 than the cubic content of the coil l6.

Assuming that the reversing valve is set so that the line 33 is connected to the low side 21 of the compressor, and the line 31 is connected to the high side 29 of the compressor, if equal quantities of liquid-refrigerant are positioned in the two heat exchangers l2- and H, the liquid level will be along the line 32 in accumulator 22 and alon the line 34 in coil IS. The refrigerant will be boiling in the accumulator 22 as it and its coils l8 pick up heat from water in which they are immersed and the liquid and gas in the coil i B and accumulator 20 will be hot and transfer heat to air passing over the coils and accumulator. The liquid in coil IE will flow through the capillary to the coil l8.

If the reversing valve is placed in its alternative position, whereby conduit 3| is connected to the low side 21 of the pump and conduit 33 is connected to the high side 29, the liquid level will assume the positions indicated by the lines 36 and 38in Fig. 2. In Fig. 2, the heat exchanger i2 is now withdrawing heat from the house air which flows over it, which heat is being transferred to the heat exchanger l4 which is losing the heat into the water in which the exchanger is positioned.

This system has been embodied in the installation shown in Figs. 3, 4 and 5. Referring to Fig. 4, the numeral 40 identifies a pipe carrying a point 4-2 which has been driven into the ground for whatever distance is necessary to reach water. It is not necessary to reach the depth of pure water. Any water will suffice. This ordinarily is an inexpensive operation. The pipe 40 is in sections and may be driven into the earth with a sledge hammer. The pipe is connected to a suction pump 44 which is driven by a motor 46. The output of this pump is taken by a flexible hose 48 into a stock tank 50. The stock tank has an outlet 52 near its bottom which is carried upwardly, externally of the tank to the point 54 which is the water level at which applicant desires the tank to operate, whereupon the water is carried along the drain 56 to a second pipe 58 with point 60 which has been driven into the ground at a point perhaps 100 feet of more from the pipe 40.

As the water system is here shown, the tank 5 3 is open topped and the pump 44 performs solely the function of raising the water out of the ground. The water returns to the ground by gravity. Actually, applicant has been delivering the water at approximately the point 62 into a drain which carries it away from his property as surface water. The arrangement shown in Fig. 4 is of great importance because the water table in many areas has I been dropping in recent decades due to the increase in the amount of pumping of water to the surface. Communities are taking steps to protect their water table. The water table that is important to communities is the water that is several hundred feet below the surface where substantially pure drinking water can be obtained. Applieants cooling system does not require pure water. Any water will do if; it

is at a proper temperature. However, the water table for drinking water is supplied by the water above and when that water is gone the drinking water table drops. Consequently. applicants system has this great merit: it withdraws the water and then returns it to the very ground from which it has been taken ior-reheatlng or recooling in intimate contact with the ground.

Applicant's system has this advantage over existing closed systems. The heat exchange surface of the closed system is limited to the surface area of the pipe that is in the ground. In applicant's system, the heat exchange takes place by the water filtering through the ground from the point 60 to the point 42. In other words. the water which has lost its heat and which is returned to the ground through the pipe 58 is much more likely to reach a desired higher tem perature for return into the system by the pipe 40 after it has worked its way through the ground than is probable where the pipes 58 and 40 are connected to each other into a closed pipe system.

Applicants system has this advantage: the weight of the water being pumped upwardly through the pipe 40 is balanced by the weight of the water descending the pipe 58 with the result that the pump performs merely a circulating function, and may be of appropriate reduced capacity with correspondingly less power consumption. To convert applicant's system into a semi-closed system, the open top stock tank is replaced by a closed tank, which becomes part of a system full of water commencing with the pipe 48 and terminating with the pipe 58.

Returning to Fig. 4, the arrangement of the outlet 52 and the drain 56 makes it possible to withdraw water from the bottom of the tank where the water is coolest. An overflow at 62 is slightly above the desired water level 54.

Disposed in'the stock tank 50 are a plurality of coils 64. A liquid refrigerant distributor 6G is positioned beneath the coils and this is tapped by lines 68 to the respective coils. The distributor 66 is supplied with refrigerant from two capillaries ID and I2 which are joined at 14 and supplied from a common capillary 1B. The discharge ends of the coils 64 are connected to an accumulator 80, which is a pipe 2 and inches in diameter. Three refrigerant gas suction lines 82, 84 and 88 are connected to the top of the accumulator 8i) and open into pipes of graduated sizes such as 88 into a single, main suction line 90.

The apparatus thus far described is housed in an unheated room 92 in applicants basement, see Fig. 3. The balance of the apparatus is positioned centrally of applicant's basement. The apparatus is clean and can be positioned at the point where the return cool air and hot air from the house can be most efficiently handled.

Continuing to refer to the drawings, the suction line 90, is carried into the main basement room near the ceiling and is connected through a reversing valve 94 to a compressor 96 of fourton capacity. The compressed refrigerant gas leaves the compressor 95 by the duct 98, and after passing through the reversing valve 94 is carried to two lines Hi0 and I02 which open into the top of an accumulator [04. The accumulator is mounted above a pair of equal capacity finned coils I06 and 108, and pipes H0 and H2 open into the upper inlet opening of the finned coils I06 and I08. The'outlets of the finned coils I06 and I08 are connected to a common pipe H4 whose sole outlet is a capillary H6, which extends up to the ceiling and over and joins the capillary I8. The compressor is driven by a five horsepower motor H8. The finned coils I08 and Ill and accumulator I84 are supported on transverse brackets I20 and I22 in a housing I24. This housing is generally separated into two chambers, a warm air chamber I28, and a cold air chamber I20, by a partition I30. The cold air intakes such as I32 open into the top of the cold air chamber I28.. A motor driven fan assembly I32 draws the cool air from the chamber I20 and forces it through the fin coils I08 and I08 into the warm air chamber and thence out room ducts such as I34.

The system as shown operates automatically after it has been set as either a heating unit or a cooling unit. Referring to Fig. 4, a power line I38 is connected to a relay I38. The output of the relay is connected by conductors arranged in parallel to the pump motor 48, the compressor motor H0, and the fan assembly motor I33. The relay I38 is actuated from a room thermostat I40. This thermostatis of that type which will close a circuit to a relay either on a falling temperature or on a rising temperature, depending upon how a manually actuated switch in the thermostat is positioned. The electrical wiring shown is conventional and need not be described in detail. At the present time, if applicant wishes to convert the system from a heating system to a cooling system, he manually throws the reversing valve 84. It is evident that the applicant Applicant has positioned along the capillary tube I8 standard windows so that he can study the could arrange an electrically operated throw switch connected to the reversing valve 84 and actuate it through a manual switch in the room thermostat I40.

The operation of the apparatus is sufficiently obvious so that it need not be described. It will,

of course, be appreciated that the amount of wacondition of the liquid refrigerant from the pipe I I4 all the way through the capillary into the coil 84. If the refrigerant going through capillary were free of gas, it would be transparent. It it not transparent but milky in appearance which indicates the presence of comparatively large quantities of gas vapor. It is, therefore, immaterial in applicant's system whether gas passes along the capillary. However, when a system is operating well, the liquid level will be above the bottom course of pipe in the coils I00 and I00, and the coils 84 will be almost full to the liquid level 54 inside the accumulator 80. With the system in reverse, the liquid level will be above the distributor pipe 88 and the liquid level in the heat exchanger I08 will be up in theaccumulator I04. In other words, in this balanced system, the refrigerant charge is such that in whatever direction the refrigerant is flowing, the refrigerant level will be above the capillary inlet on the heat exchanger that is performing the cooling function and will be up in the accumulator in the heat exchanger unit that is performing the heating function. For practical purposes, the capillary is never blown out by gas. It will be appreciated that this becomes of great importance when the system is operated within 24 hours as both a heating and a cooling unit. Many climates where the play between night and day temperatures is very great, fifty or sixty degrees, require a little heatter passed through the tank per hour will vary withthe load. It will also vary with the temperature of the water and this temperature does vary substantially from September, when the system is first turned over to heating. to the coolest months. During the month of February, the temperature of the water from the tank from the ground was 56 degrees and the temperature of the water .as it left the tank'to return-to the The situation occurs in many localities in the spring and fall of the year. The advantage of applicant's balanced system is that it can be converted from a heating to a cooling system without any adjustment being made in the refrigerant line itself other than the act of throwing the reversing valve. Applicant's is an open duct system.

The accumulator acts as a muiller. ZAs heretofore mentioned, .the pound of the pump is very loud where the shock of the compressed gas is contained in a pipe system. of. constant diameter prior to liquif-ying a refrigerant. Applicant's accumulator performs a duelfunction. When the pressor,.that is, on the side leading to the accumulator I04 and coils l0 and Ill-the temperature is about 133 degrees Fahrenheit and the pressure about 190 pounds. .On the low side, that is, in the suction line 00, the pressure is about 28 pounds and the temperature is about 30 degrees Fahrenheit. With the temperature of the compressed gas at 133 degrees Fahrenheit, a flow of very warm air can be maintained into the ducts I with slugs of gas mixed with liquid refrigerant.

rtant, the first feature resides in the I accumulator is acting in the heat exchanger which is performing the heating function, the accumulator functions as a mullier. on the other hand,'when the accumulator is .in the heat ex-f .changer which is performingthe coolingfunctiomthe accumulator with its'large surface area for a liquid level assists in rapid boiling of the The balanced has irrespective of .4

the presence of a reversing valve. The use of heat exchangers having substantially equal volumetric capacity eliminates the use of valves in the refrigerant line. Referring to Figs. 3, 4 and 5, if the reversing valve- 34 is omitted, applicant's system maintains the correct liquid levelsin the two heat exchangers. It should be noted that cold air, referring to Fig. 4, is brought in beneath the coils I08 and I08. The lower end of these coils is comparatively cool because of the presence of liquid refrigerant, and, therefore, has little heat transfer eflect upon the air. This is to be contrasted with the ordinary way of applying air to a condenser in a refrigerating system where no care is taken as to the direction of the flow of the air.

Having thus described my invention, what I claim is:

g 1. A reversible heat exchange system comprising a pair of heat exchangers having approximately equal volumetric capacity,- a tube having auras a restricted passageway therein connecting the -lower portions of said heat exchangers to each other, an accumulator connected to the top of each heat exchanger, a duct connecting each accumulator to a reversing valve assembly, a compressor, and ducts connecting the valve assembly to the high and low 'side of the compressor, said reversing valve being so arranged that the high side of the compressor can be connected to either accumulator and while so connected, the low side of the compressor will be connected to the other heat exchanger.

2. A reversible heating and cooling system comprising a housing having an inlet and an outlet therein for passing fluid to be heated or cooled through the housing, a heat exchanger consisting of an accumulator tank connected to a coil positioned in said housing, a second heat exchanger positioned outside the housing and having a volumetric capacity substantially equal to that of the first heat exchanger, a tube having a restricted passageway therein connecting the lower portions of said heat exchangers to each other, a compressor, a duct connecting the accumulator tank to the high side of the compressor, a duct connecting the other heat exchanger to the low side of the compressor, and a reversing valve positioned in both of said ducts for connecting the accumulator tank to the low side of the compressor and the second heat exchanger to the high side of the compressor.

3. A reversible heating and cooling system comprising a housing having an inlet and an outlet therein for passing fluid to be heated or cooled through the housing, an accumulator tank mounted in said housing, a coil for refrigerant positioned beneath the accumulator, a plurality of ducts connecting the accumulator tank to the coil, a compressor having a high side and a low side, a duct connecting the high side of the compressor to the accumulator tank, a heat exchanger positioned outside the housing and having a volumetric capacity substantially equal to the combined capacity of the accumulator tank and the coil, a tube having a restricted passageway therein connecting the lower portions of said coil and said heat exchanger, a duct connecting the heat exchanger to the low side of the compressor, and a reversing valve positioned in both of said ducts for connecting the accumulator tank to the low side of the compressor and the heat exchanger to the high side of the compressor.

4. A reversible heating and cooling system comprising a housing having an inlet and an outlet therein for passing fluid to be heated or cooled through the housing, a pair of heat exchangers each consisting of an accumulator tank connected to a coil, one positioned in the housing and the other outside the housing, said heat exchangers having approximately equal volumetric capacity, a tube having a restricted passageway therein connecting the lower por- 8 ing the accumulator tanks to the high and low sides respectively or the compressor, and a tube having a restricted passageway therein connecting the lower ends of the coils of one exchanger to the lower ends of the coils of the other exchanger.

6. A reversible heat exchange system comprising a pair of heat exchangers having approximately equal volumetric capacity, a capillary tube connecting the lower portions of said heat exchangers to each other, an inlet near the top of each heat exchanger, a duct connecting each inlet to a-reversing valve assembly, a compressor, ducts connecting the valve assembly to the high and low side of the compressor, said reversing valve being so arranged that the high side of the compressor can be connected to either heat exchanger and while so connected, the low side of the compressor will be connected to the other heat exchanger, and a liquid refrigerant having a volume approximating the volume of one heat exchanger in the system.

'7. A reversible heat exchange system comprising a pair of heat exchangers having approxi mately equal volumetric capacity, a capillary connecting said heat exchangers to each other, a compressor having a high side and a low side, ducts connecting the heat exchangers t0 the high and low sides respectively of the compressor, one of said exchangers being positioned within a tank, an inlet and an outlet for said tank, a pipe connected to the inlet and extending into the ground, a pipe connected to the outlet of the tank and extending into the ground, and a pump for circulating liquid from the first pipe through the tank and out the second pipe.

8. A reversible heat exchange system comprising a pair of heat exchangers having approximately equal volumetric capacity, a capillary connecting said heat exchangers to each other, a compressor having a high side and a low side, ducts connecting the heat exchangers to the high and low sides respectively of the compressor, one of said exchangers being positioned within a tank, an inlet and an outlet for said tank, a pipe connected to the inlet and extending into the ground, a pipe connected to the outlet of the tank and extending into the ground, and a pump for circulating liquid from the first pipe through the tank and out the second pipe at approximately the same level as the intake end of the first pipe.

9. A reversible heat exchanger system comprising a pair of heat exchangers having substantially equal volumetric capacity, each heat exchanger consisting of an accumulator tank connected to coils positioned therebelow, a compressor, ducts connecting the accumulator tanks to the high and low sides respectively of the compressor, a reversing valve positioned in both ducts for reversing the connections of the two accumulators to the compressor, and a liquid refrigerant having a volume approximating the volume of one exchanger in the system.

10. A reversible heat exchanger system comprising a. compressor, a reversing valve, ducts connecting the reversing valve to the compressor, a heat exchanger comprising an accumulator and a connected, suspended coil, a duct connecting the accumulator to the reversing valve, a second heat exchanger comprising an accumulator of lesser volume than the accumulator of the first exchanger and connected to a depending coil having sufliciently more capacity than the capacity of the coil of the first exchanger so 10 that the volumetric capacities of the two ex- UNITED STATES PATENTS changers are approximately equal, and a tube Number Name Date connecting the coils for one heat exchanger to 2 135 742 Brace Nov. 8. 1938 the coils of the other heat exchanger, there be- 2:148:415 Labberton 21 1939 ing a restricted passageway in said tube so that 5 2 165 854 Headrick July 1939 it may act as a refrigerant flow control. 2'167873 Crawford 1939 FRANK KRUEGER- 2,342,174 Wolfert -1 Feb. 22, 1944 REFEREN s CIT D 2,433,720 Smith Mar. 3 1948 C E 2,443,500 Goddard June 15, 1948 The following references are of record in the 10 2,486,608

4 file of this patent: MacDougall Nov 1, 19 9 

